Eight years ago, an economist produced a new theory that international trade played a major role in an American tragedy: the immense killing in the late 19th century that brought the North American bison close to extinction.

The idea challenged the narrative that the slaughter of the bison, or buffalo, was mainly caused by the eagerness of American and European settlers to turn grasslands into farms and move American Indians off the land.

Donna Feir, an economist at the Federal Reserve Bank of Minneapolis was a graduate student in Vancouver when the new theory emerged, and it still left a big question for her: “My first thought was what happened to the people that were relying on this animal?” she said.

She and two colleagues at her Canadian teaching institution, the University of Victoria, recently published an answer that seems obvious on the surface, yet bold and provocative in its detail. The bison slaughter, they concluded, created so great a loss of wealth for the tribes that most relied on the animals, that it has lasted up until now.

The tribal nations that were bison-reliant in yesteryear have per capita incomes today that are 20 percent to 40 percent below the average of all American Indian nations, their research showed.

Economist Donna Feir has researched how the slaughter of the bison on the American plains in the 1870s was not just an ecological disaster but an economic one.

Such work has moved beyond academic circles into books and articles that, for instance, have reshaped popular understanding of wealth along gender and racial lines. Feir describes it as studying the “long arm” of history — “how historic shocks carry forward in fundamental and important ways.”

She and her co-authors wrote that the bison slaughter and shunting of American Indians onto reservations hold lessons about the danger of relying too much on few resources and the lasting trauma that rapid change can cause.

“When the bison were eliminated, the resource that underpinned these societies vanished in an historical blink of the eye,” they wrote in the paper.

Their conclusions and data are now being scrutinized in peer review as editors of economic journals consider publishing the paper. The Minneapolis Fed’s Center for Indian Country Development in late November published it in a form that academics call a working paper.

The paper offers a model for studying the destruction of resources, said Patrice Kunesh, the center’s director.

“I could project this onto several other situations,” she said, suggesting the loss of minerals on native land in Oklahoma and the near-wipeout of the beaver in the American Northeast, also in the late 19th century.

Tackling the bison slaughter and removal of natives from the plains of the U.S. and Canada was particularly ambitious. The scale of the change was large — involving millions of people, a huge swath of territory and the continent’s largest animal.

Americans learn of it at a young age and then encounter its legacy by traveling the West or interacting with Indian tribes. Even a trip to the Minnesota Zoo, which is raising a herd of several hundred bison, brings the tragedy alive again.

“It’s a stain on our nation’s legacy, and I think most people recognize it,” said Steven Rinella, whose 2009 book “American Buffalo: In Search of a Lost Icon” blends the story of the animal’s evolution with his experience of winning a rare chance to hunt one in the Alaskan wild.

Now host of the Netflix show “MeatEater,” Rinella said his research of the bison more than a decade ago was shaped by historians and environmentalists and that he likes to stay up on the discussion.

“It’s fascinating to think about” the economic effects, he said. “I’m really curious about the agendas there. I’m sure it will re-enliven our cultural feelings of guilt about what happened.”

He thinks that discussions of the slaughter and its effects are complicated by the difficulty of imagining the plains and bison as they were.

“We’re almost incapable of comprehending the abundance of the herd of animals that existed here 200 years ago,” Rinella said. “We’re not equipped to even visualize it. There’s nothing comparable.”

Tens of millions of bison roamed from the southeastern and southwestern U.S. through nearly the entire country and up into the high mountain ranges of western Canada. Feir, Gillezeau and Jones describe the bison-reliant Indians as the tallest and best-off people on the continent as Europeans started to settle, “at least as well off as their average European counterparts.”

But the number of bison started to decline in the 1600s when tribes began to use horses to hunt them and European settlers pushed them out of the eastern U.S. toward the plains. Climate change also played a role as the grasslands dried up in the 18th and early 19th centuries and their territory narrowed.

The final blow came in a 15-year period right after the Civil War, when bison were killed in a voracious spree influenced by European demand for hides, emergence of the railroad and the desire of Americans to confine Indians to smaller territory.

“I would not seriously regret the total disappearance of the buffalo from our western plains, in its effect upon the Indians,” Columbus Delano, then the secretary of the interior, wrote in 1873.

Feir and her colleagues concentrated their research on that time, when the bison herd went from around 8 million to 1,000. They first turned to surveys done in the 1880s by the Smithsonian Institution when its anthropologists, anticipating the extinction of the bison, tracked the decline and obtained specimens to preserve for displays. They then used census records and other data to study the effects on the nutrition, economic activity and mobility of Indian nations.

In the 61-page paper, they explain their data choices and lay out the formulas they used for calculations.

After reading the paper at the request of the Star Tribune, Andrew Isenberg, a history professor at the University of Kansas and author of “The Destruction of the Buffalo: An Environmental History,” said he believes Feir, Gillezeau and Jones overlooked some ecological factors that hurt the bison and some adaptations that helped the Indians.

For instance, while they were supposed to be confined to reservations in the post-bison era, American Indians almost immediately became involved in the economic activities of small towns on the frontier. Researchers are just starting to understand that phenomenon, he said.

“Settler colonialism was really bad for Indian health and wealth, absolutely,” Isenberg said. “But when you start looking at it closely, it becomes much more complex.”

Sebastian Braun — director of the American Indian Studies Program at Iowa State University and author of “Buffalo Inc.: American Indians and Economic Development” — said the path from the slaughter to today’s economic difficulties for tribes is not a straight one.

The development of cattle operations by tribes that relied on the bison was disrupted when reservations were carved up among tribal members in the 1890s and early 1900s. The building of dams hurt some of those nations, too, he said, and natural disasters took a toll.

Today, 500,000 bison live in the U.S. and Canada, nearly all in captivity.

“I don’t want to underestimate the impact of the bison slaughter, but I do see that tribes built successful economies after that, which were then destroyed,” Braun said.

To him, the slaughter serves as a warning about resource depletion. With today’s environmental movement and conservation efforts, Braun said, “we don’t think that could happen … but it’s the original story of finite resources and infinite demand.”

Feir said she and her colleagues will continue to address criticisms of their research. They have also started presenting it to native leaders and communities in the U.S. and Canada.

“It’s very salient to many,” she said. “It speaks to their experience and knowledge of their own histories.”

Evan Ramstad is a team leader in business news, working with reporters who cover the food industry from field to fork. He also writes about technology, banking and the economy.